Emergency engine shutoff apparatus and accident determining apparatus for ship

ABSTRACT

An emergency engine shutoff apparatus for shutting off an engine in an accident of a ship having a hull and an outboard engine system is provided which includes: an acceleration detector for detecting an acceleration applied in a longitudinal direction of the hull and an acceleration applied in a vertical direction of the hull; an accident determining apparatus for determining that a collision accident occurred when the acceleration applied in a longitudinal direction of the hull exceeds a threshold, and for determining that a capsize accident occurred when a roll angle of the ship exceeds a threshold, the roll angle being arithmetically operated by using the acceleration in the vertical direction; and an engine shutoff apparatus for shutting off the engine by stopping fuel supply to the engine when it is determined that a collision accident or a capsize accident occurred.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an emergency engine shutoff apparatuswhich shuts off an engine for the safety of crew in an accident of aship having a hull and a propulsion apparatus having the engine as adriving source.

PRIOR ART OF THE INVENTION

An emergency engine shutoff apparatus for shutting off a propulsionapparatus engine of a ship when a driver of the ship falls in the wateris disclosed in Japanese Utility Model Examined Application PublicationNo. 5-48344 and Japanese Patent Application Laid-Open No. 2-221637. Thistype of apparatus comprises: an emergency switch provided for shuttingoff an engine in operation; a switch operating member which is removablymounted to an operation section of the emergency switch for holding theemergency switch in a non-operated state; and a rope or the like forconnecting the switch operating member to a part of a body of a shipnavigator, so that when the ship navigator falls in the water, theswitch operating member is removed from the emergency switch to causethe emergency switch to be in the non-operated state to shut off theengine.

As described above, conventional emergency engine shutoff apparatusesfor ship comprise means for shutting off an engine when a ship navigatorfalls in the water, but did not comprise means for shutting off anengine when a hull of the ship collides with something or capsizes.

As a result, in a conventional ship, when an accident occurs such as acollision with something or a capsize of the ship, if a ship navigatorgets injured so badly that he/she cannot handle the ship and remains inthe ship, an engine of the ship could not be shut off. So, thecircumstance was dangerous because if crews other than the shipnavigator were thrown into the water in the collision or capsize, thecrews in the water might get injured or even die by contacting arotating propeller.

In addition, in a conventional ship, since a propulsion power iscontinuously supplied after the collision, the hull might run away in anunexpected direction, which might cause a secondary accident.

Furthermore, since a conventional ship was not provided with means forshutting off an engine when a collision accident or a capsize accidentoccurs, fuel is continuously supplied to the engine after the accident,which might result in fire breakout due to the engine.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an emergency engineshutoff apparatus for ship which can immediately shut off an engine forimproving safety when a ship causes a collision accident or a capsizeaccident.

The present invention relates to an emergency engine shutoff apparatuswhich shuts off an engine in an accident of a ship having a hull and apropulsion apparatus having the engine as a driving source. In thepresent invention, an emergency engine shutoff apparatus is providedwith an acceleration detector for detecting an acceleration applied ontothe hull; an accident determining apparatus having accident determiningmeans for determining a presence/absence of an occurrence of an accidentbased on an output of the acceleration detector, on the premise that acollision of the hull with something and/or a capsize of the hull is anaccident to be determined; and engine shutting off means in accidentwhen the accident determining apparatus determines that an accidentoccurred.

When a ship causes a collision accident or a capsize accident, anacceleration applied onto the hull changes differently from a normaloperation, thereby, as described above, an acceleration detector fordetecting an acceleration applied onto the hull enables a determinationof a presence/absence of an occurrence of a collision accident or acapsize accident based on the output of the acceleration detector, sothat an ignition operation of the engine can be stopped when it isdetermined that an accident occurred, or the engine can be shut off bystopping a fuel supply to the engine.

In this way, according to the present invention, an engine is shut offin a collision accident or a capsize accident, thereby if crews otherthan a ship navigator are thrown into the water in a collision orcapsize, the probability that the crews in the water might contact arotating propeller can be eliminated.

Also, according to the present invention, an engine is shut off in acollision accident, thereby even if a ship navigator gets injured sobadly that he/she cannot handle a ship, the probability that a hull runsaway in an unexpected direction can be eliminated.

In one preferred aspect of the present invention, the above describedacceleration detector is provided for detecting at least an accelerationGx applied in a longitudinal direction of a ship. In this case, anaccident determining apparatus is comprised to include an accidentdetermining means for determining that a hull collided with somethingwhen an acceleration Gx applied in the longitudinal direction of theship exceeds a threshold in an acceleration or deceleration of the ship.

In another preferred aspect of the present invention, the abovedescribed acceleration detector is provided for detecting at least anacceleration Gy applied in a vertical direction of a ship. In this case,an accident determining apparatus is comprised to include an accidentdetermining means for determining that a ship capsized when a roll angleθr of the ship exceeds a preset threshold, the roll angle θr beingobtained based on an arccosine value: cos⁻¹ Gy of the acceleration Gyapplied in the vertical direction of the ship.

In a further preferred aspect of the present invention, the abovedescribed acceleration detector is provided for detecting at least anacceleration Gz applied in a lateral direction of a ship. In this case,an accident determining apparatus is comprised to include an accidentdetermining means for determining that a ship capsized when a roll angleθr of the ship exceeds a preset threshold, the roll angle θr beingobtained based on an arcsine value: sin⁻¹ Gz of the acceleration Gzapplied in the lateral direction of the ship.

In a further preferred aspect of the present invention, the abovedescribed acceleration detector is provided for detecting anacceleration Gx applied in a longitudinal direction and an accelerationGy applied in a vertical direction of a ship. In this case, an accidentdetermining apparatus is comprised to include an accident determiningmeans for determining that a hull collided with something when anacceleration Gx applied in the longitudinal direction of the shipexceeds a threshold, and that the ship capsized when a roll angle θr ofthe ship exceeds a preset threshold, the roll angle θr being obtainedbased on an arccosine value: cos⁻¹ Gy of the acceleration Gy applied inthe vertical direction of the ship.

In a further preferred aspect of the present invention, the abovedescribed acceleration detector is provided for detecting anacceleration Gx applied in a longitudinal direction and an accelerationGz applied in a lateral direction of a ship. In this case, an accidentdetermining apparatus is comprised to include an accident determiningmeans for determining that a hull collided with something when anacceleration Gx applied in the longitudinal direction of the shipexceeds a threshold in an acceleration or deceleration of the ship, andthat a ship capsized when a roll angle θr of the ship exceeds a presetthreshold, the roll angle θr being obtained based on an arcsine value:sin⁻¹ Gz of the acceleration Gz applied in the lateral direction of theship.

In a further preferred aspect of the present invention, the abovedescribed acceleration detector is provided for detecting anacceleration Gz applied in a lateral direction and an acceleration Gyapplied in a vertical direction of a ship. In this case, an accidentdetermining apparatus is comprised to include an accident determiningmeans for determining that the ship capsized when a roll angle of theship exceeds a preset threshold, the roll angle θr being obtained basedon an arctangent value: tan⁻¹(Gz/Gy) of a ratio (Gz/Gy) between theacceleration Gz applied in the lateral direction and the acceleration Gyapplied in the vertical direction of the ship.

In a further preferred aspect of the present invention, the abovedescribed acceleration detector is provided for detecting anacceleration Gx applied in a longitudinal direction, an acceleration Gyapplied in a vertical direction of a ship, and an acceleration Gzapplied in a lateral direction of a ship. In this case, an accidentdetermining apparatus is comprised to include an accident determiningmeans for determining that a hull collided with something when anacceleration Gx applied in the longitudinal direction of the shipexceeds a threshold in an acceleration or deceleration of the ship, andthat the ship capsized when a roll angle θr of the ship exceeds a presetthreshold, the roll angle θr being obtained based on an arctangent valuetan⁻¹ (Gz/Gy) of a ratio (Gz/Gy) between the acceleration Gz applied inthe lateral direction and the acceleration Gy applied in the verticaldirection of the ship.

When the above described propulsion apparatus is an outboard enginesystem, and the outboard engine system is provided with a controller forcontrolling a trim angle of the outboard engine system, controlling anengine, and performing a process to construct the above describedaccident determining apparatus, the above described accelerationdetector is preferably provided in the controller.

In such a structure, when an outboard engine system is mounted to ahull, an acceleration detector does not have to be mounted to the hull,and no wire harness is needed to be extended for connection between anacceleration detector and a controller, thereby the outboard enginesystem can be simply mounted. In addition, when an outboard enginesystem has an acceleration detector mounted therein which is adapted todetect at least an acceleration Gy applied in a vertical direction, itsinclination relative to the vertical direction of the outboard enginesystem can be detected based on an output of the acceleration detector,as the result of that, when the information on the inclination relativeto the vertical direction of the outboard engine system is used incontrolling a trim angle of the outboard engine system, the abovedescribed acceleration detector can be used as a detector for acquiringthe information.

When an outboard engine system is comprised so that fuel is suppliedthereto by a fuel injection apparatus having an injector and a fuel pumpfor supplying fuel to the injector, the engine shutting off means inaccident can be comprised so as to shut off the engine by stoppingdriving at least one of the fuel pump and the injector to stop the fuelsupply to the engine when the accident determining apparatus determinesthat an accident occurred.

As described above, the engine shutting off means in accident iscomprised so as to shut off the engine by stopping a fuel supply to theengine when the accident determining apparatus determines that anaccident occurred, the probability that a fire breaks out due to theengine can be eliminated because the fuel supply to the engine isstopped in a collision accident or a capsize accident.

As described above, when an engine is comprised so that fuel is suppliedthereto by a fuel injection apparatus having an injector and a fuel pumpfor supplying fuel to the injector, alternatively, the engine shuttingoff means in accident can be comprised of: fuel supply stopping meansfor stopping fuel supply to the engine by stopping driving at least oneof the fuel pump and the injector when the accident determiningapparatus determines that an accident occurred; and ignition operationstopping means for stopping any ignition operation of the engine whenthe accident determining apparatus determines that an accident occurred.

In order to prevent a fire breakout in an accident, as described above,it is preferred to stop any fuel supply to the engine in the accident,but the configuration of engine shutting off means in accident is notlimited to the one described above, and the engine shutting off means inaccident may be comprised only of ignition operation stopping means forstopping any ignition operation of the engine when the accidentdetermining apparatus determines that an accident occurred.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the invention will beapparent from the detailed description of the preferred embodiments ofthe invention, which is described and illustrated with reference to theaccompanying drawings, in which;

FIG. 1 is a schematic side view showing an example of a ship to whichthe present invention is applied, with a part of the ship being crosssectioned;

FIG. 2 is a schematic view showing a structure of hardware of anembodiment according to the present invention;

FIG. 3 is a block diagram of a general structure showing main parts ofan apparatus having means which is comprised of a microprocessor in anembodiment of the present invention;

FIG. 4 is a side view of main parts showing an acceleration detectorwhich is mounted in an outboard engine system and an acceleration whichis detected by the acceleration detector in a first embodiment of thepresent invention;

FIG. 5 is a graph showing an example of changes in accelerations whichare detected by the acceleration detector of FIG. 4;

FIG. 6 is a front view of main parts showing an acceleration detectorwhich is mounted in an outboard engine system and an acceleration whichis detected by the acceleration detector in a second embodiment of thepresent invention;

FIG. 7 is a side view showing the outboard engine system of FIG. 6;

FIG. 8 is a front view showing a state of an outboard engine system whena ship having the outboard engine system of FIG. 6 and FIG. 7 is rolled;and

FIG. 9 is a graph showing the changes in accelerations Gx, Gy and Gzwhich are obtained by an acceleration detector when a ship is kept in astopped state and only roll angles of a hull are changed in theembodiment of FIG. 6 to FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, with reference to the drawings, preferred embodiments of thepresent invention will be explained in detail below.

The present invention can be widely applied to ships having a hull and apropulsion apparatus having an engine as a driving source, but in thepresent embodiment, as shown in FIG. 1, the present invention is appliedto a ship 1 which uses an outboard engine system as a propulsionapparatus. In FIG. 1, a reference numeral 2 denotes a hull having asteering wheel 2 a, a throttle lever 2 b, a cockpit 2 c, and the likefor steering, and 3 denotes an outboard engine system.

The outboard engine system 3 includes an outboard engine body 303 havingan engine 301 and a propeller 302 which is driven by the engine, andbrackets 304 which are provided on both sides of a front part of theoutboard engine body, and the outboard engine system 3 is mounted to atransom 2 d of the hull 2 via the brackets 304. Between the right andleft brackets 304, a power trim system is provided to cause the outboardengine body 303 to be driven by a driving source such as a motor or ahydraulic cylinder to rotate about a rotation shaft 305 which isincluded in the brackets 304.

FIG. 2 shows an example of a hardware structure of a control sectionwhich is comprised of a control apparatus for controlling the engine ofthe outboard engine system, a control apparatus for the power trimsystem, and an emergency engine shutoff apparatus according to thepresent invention. In FIG. 2, a reference numeral 3 denotes an outboardengine system, and 4 denotes a remote control unit which is mounted nearthe cockpit 2 c in the hull 2.

In FIG. 2, a reference numeral 310 denotes the power trim systemprovided to the outboard engine system, 311 denotes a controller of thepower trim system, and 312 denotes an engine controller. The power trimsystem 310 includes a power trim motor 315, a trim mechanism foradjusting an inclination of the outboard engine body 303 relative to thehull 2 using a power trim motor as a driving source, and a trim anglesensor 316 for detecting an inclination of the outboard engine body 303relative to the hull 2.

The controller of the power trim system 311 includes a microprocessor317 having a CPU, an acceleration detector 318, and a motor drivecircuit 319 for supplying a drive current to the power trim motor 315.

Not shown in FIG. 2, but the engine controller 312 also has amicroprocessor. The engine controller 312 causes the microprocessor toexecute a predetermined program to control an ignition timing of theengine, and to control fuel supplies to the engine.

A remote control unit 4 includes: an auto/manual mode selection switch401 which is operated by a driver for selecting an operation modebetween an automatic control mode and a manual mode; trim command switch402 which is operated by a driver for operating the outboard enginesystem to a trim up direction and a trim down direction individuallywhile the manual mode is selected; and a display device 403 fordisplaying a current trim angle and a current operation mode.

In the present embodiment, the microprocessor included in the power trimcontroller 312 is used to perform a process to construct an emergencyengine shutoff apparatus according to the present invention. FIG. 3 is ablock diagram of a general structure of a part related to an emergencyengine shutoff apparatus of the present embodiment. In FIG. 3, areference numeral 2 denotes a hull, 3 denotes an outboard engine systemhaving an outboard engine body 303 and the power trim system 310.

In the present embodiment, a fuel injection apparatus 320 is used tosupply fuel to the engine in the outboard engine body. The fuelinjection apparatus 320 is a known one that includes an injectorprovided to inject fuel to a space for fuel injection such as an insideof an intake pipe of an engine, a fuel pump for supplying the fuel tothe injector, and an injector control section for controlling the fuelinjection duration by the injector so as to cause the injector to injecta predetermined amount of fuel.

The emergency engine shutoff apparatus according to the presentinvention is comprised of: an acceleration detector 318; an arithmeticoperating section 21 for obtaining parameters which are necessary todetermine an accident based on an output of the acceleration detector318; an accident determining means 24 for determining a presence/absenceof an accident by using the parameters obtained by the arithmeticoperating section 21; and engine shutting off means in accident 25 forshutting off the engine when the accident determining means 24determines that an accident occurred.

The accident determining means 24 determines whether an accident hasoccurred or not based on an output of the acceleration detector 318, onthe premise that a collision with something and/or a capsize of the hull2 is an accident to be determined. In the present embodiment, theacceleration detector 318 is comprised of a two-axis acceleration sensorprovided for detecting an acceleration Gx applied in a longitudinaldirection and an acceleration Gy applied in a vertical direction of thehull 2, and the accident determining means 24 is comprised so as todetermine that the hull 2 collided with something when an accelerationGx applied in the longitudinal direction of the ship exceeds a thresholdin an acceleration or deceleration of the ship, and that the shipcapsized when a roll angle θr of the ship exceeds a preset threshold,the roll angle θr being obtained based on an arccosine value of theacceleration Gy applied in a vertical direction of the ship.

Herein, among the planes that include the central axis line of thepropeller 302 of the outboard engine system 3, the plane which extendsalong the vertical direction when the hull 2 floats still on the stillwater is set to be a reference plane, and the direction which extendsalong the water line of the hull 2 on the reference plane is set to be alongitudinal direction of the ship. The reference plane is parallel tothe sheet surface of FIG. 1, and the longitudinal direction of the shipruns along the straight line L of the FIG. 1. Also, a straight line O-Owhich runs along the outboard engine system 3 at a certain mountingangle θI relative to the longitudinal direction of the ship on thereference plane when the outboard engine system is located at a positionfor the minimum trim (the trim angle is zero) is set to be a referenceaxis line of the outboard engine system. The angle of the reference axisline O-O of the outboard engine system relative to the verticaldirection on the reference plane is set to be an inclination θo, and theangle obtained by subtracting the mounting angle θI from an angle of thereference axis line of the outboard engine system relative to thelongitudinal direction of the ship on the reference plane is set to be atrim angle θt of the outboard engine system. In addition, theinclination of the hull on the plane which includes the reference axisline O-O of the outboard engine system and is orthogonal to thereference plane is set to be a roll angle θr of the ship.

In the present embodiment, since the acceleration sensor 318 is mountedin the controller of the power trim system 311 which is provided in theoutboard engine system, for convenience, the direction along thereference axis line O-O is set to be the vertical direction (Y-axisdirection) of the ship, and the direction orthogonal to the referenceaxis line on the reference plane is set to be the longitudinal direction(X-axis direction) of the ship, as shown in FIG. 4. With thelongitudinal direction and the vertical direction of the ship beingdefined as described above, the longitudinal direction and the verticaldirection of the ship change depending on a trim angle of the outboardengine system, but it causes no adverse effect in detecting an accident.

The acceleration detector 318 used in the present embodiment detects: asshown in FIG. 4, an acceleration applied in the direction (Y-axisdirection) along the reference axis line O-O of the outboard enginesystem 3 as an acceleration Gy applied in a vertical direction of theship; and a an acceleration applied in the direction (X-axis direction)orthogonal to the reference axis line O-O on the reference plane as anacceleration Gx applied in a longitudinal direction.

In this case, the arithmetic operating section 21 is comprised oflongitudinal direction acceleration reading means 22 for reading anacceleration Gx applied in a longitudinal direction from an output ofthe acceleration detector 318; and roll angle arithmetic operating means23 for arithmetically operating a roll angle θr of the ship.

The longitudinal direction acceleration Gx detected by the accelerationdetector 318 changes like the curving line a of FIG. 5 when the ship isaccelerated, and changes like the curving line b of FIG. 5 when the shipis decelerated in a normal sailing. The horizontal axis of FIG. 5represents the elapsed time t.

Now, assuming that another ship collides (bumps) the ship in the rearpart thereof, the longitudinal direction acceleration Gx changes likethe curving line c of FIG. 5 in a wider range than the acceleration(curving line a) when the ship is accelerated in a normal sailing. Whenthe ship collides with something, the longitudinal directionacceleration −Gx changes like the curving line d of FIG. 5 in a widerrange than the deceleration (curving line b) when the ship isdecelerated in a normal sailing. Therefore, a preset of an appropriatethreshold Gd for collision enables a determination of a collision ofsomething with the ship when a longitudinal direction acceleration Gxexceeds the threshold Gd for collision in accelerating of the ship, andalso enables a determination of a collision of the ship with somethingwhen a longitudinal direction acceleration −Gx exceeds the threshold Gdfor collision in decelerating of the ship.

The detection of an acceleration Gy applied in a vertical direction ofthe ship allows an arithmetic operation of a roll angle θr of the shipusing an arithmetic expression θo=cos⁻¹(Gy/Gg)=cos⁻¹ Gy, where Gg isgravitational acceleration (=1) and Gy is acceleration in the verticaldirection. The roll angle arithmetic operating means 23 shown in FIG. 3obtains an arccosine value of an acceleration Gy detected by theacceleration detector 318 so as to arithmetically operates a roll angleof the ship, so that the processed value is given to the accidentdetermining means 24.

In this case, the accident determining means 24 determines that the shipcollided with something at the front part thereof when the acceleration−Gx applied in the longitudinal direction exceeds the threshold Gd forcollision in decelerating the ship, and determines that something hitthe ship in the rear part thereof when the acceleration Gx applied in alongitudinal direction exceeds the threshold Gd in accelerating theship. Also, when a roll angle θr of the ship exceeds the presetthreshold θrs, the accident determining means 24 determines that theship capsized.

When accident determining means 24 determines that a collision accidentor a capsize accident occurred, the engine shutting off means inaccident 25 shuts off the engine. As in the present embodiment, in acase where fuel is supplied to an engine by using a fuel injectionapparatus 320 which has an injector and a fuel pump for supplying fuelto the injector, the engine shutting off means in accident 25 may becomprised so as to, when the accident determining means 24 determinesthat an accident occurred, shut off the engine by stopping driving atleast one of the fuel pump and the injector to stop the fuel supply tothe engine.

In a case where an engine is comprised so that fuel is supplied theretoby a fuel injection apparatus 320, the engine shutting off means inaccident 25 may also be comprised of fuel supply stopping means forstopping fuel supply to the engine by stopping driving at least one ofthe fuel pump and the injector when the accident determining means 24determines that an accident occurred, and ignition operation stoppingmeans for stopping an ignition operation of the engine when the accidentdetermining means 24 determines that an accident occurred.

Alternatively, the engine shutting off means in accident 25 may becomprised only of the ignition operation stopping means for stopping anignition operation of the engine when the accident determining means 24determines that an accident occurred.

In the present embodiment, an accident determining apparatus for ship iscomprised of the acceleration detector 318, the arithmetic operatingsection 21, and the accident determining means 24, and the accidentdetermining apparatus and the engine shutting off means in accident 25comprise an emergency engine shutoff apparatus.

An acceleration Gy in the vertical direction which is detected by anacceleration detector changes in response to a change in a roll angle ofa ship as well as a change in a pitch angle. Therefore, a capsizethreshold θrs to be compared with the above described roll angle θo(which is sometimes a pitch angle actually) is set to be a value whichis sufficiently larger than a critical value of a roll angle and a pitchangle of the ship in a normal sailing (a value that is impossible unlessa ship capsizes, such as 90 degrees or more).

In the above explanation, an accident that a ship is collided bysomething in a rear part thereof and an accident that a ship collideswith something at a front part thereof are distinguished from each otherfor determination, but when a collision is an accident to be determined,the accident determining means may also be comprised so as to determinethat an accident occurs when a ship collides with something, so that theaccident determining means can determine an occurrence of an accident bycomparing the absolute value of an acceleration Gx with a threshold Gdfor collision, without distinguishing between a collision accident and abump accident.

FIG. 6 and FIG. 7 show a second embodiment of the present invention. Inthe present embodiment, as shown in FIG. 6 and FIG. 7, as anacceleration detector 318, a three-axis acceleration sensor is usedwhich is able to detect accelerations in three axes direction: anacceleration Gx applied in a longitudinal direction; an acceleration Gyapplied in a vertical direction (a direction along the reference axisline O-O of an outboard engine system); and an acceleration Gz appliedin a lateral direction (a direction orthogonal to the longitudinaldirection and the vertical direction).

In the present embodiment, accelerations Gx, Gy, and Gz in the three x,y, and z axis directions respectively which are detected when a ship isstopped and is only under a roll motion change as shown in FIG. 9. Thatis, since the ship is not moving in the longitudinal direction, theacceleration Gx applied in the longitudinal direction is constantlyzero, and the waveform representing the change of the acceleration Gyapplied in the vertical direction forms a cosine waveform, and thewaveform representing the change of the acceleration Gz applied in thelateral direction forms a sine waveform.

With using such an acceleration detector, a detected value of anacceleration Gx applied in the longitudinal direction is compared with athreshold Gd for collision, so as to be able to determine if a collisionaccident between the ship and something has occurred or not.Furthermore, by obtaining an arctangent value: tan⁻¹(Gz/Gy) of a ratio(Gz/Gy) between a detected value of an acceleration Gz applied in thelateral direction and a detected value of an acceleration Gy applied inthe vertical direction, a roll angle θr of the ship (see FIG. 8) isarithmetically operated, so as to be able to determine if a capsizeaccident has occurred when the processed roll angle θr exceeds athreshold θrs.

In addition, as described above, when a three-axis acceleration sensoris used as the acceleration detector 318, a roll angle θr can beobtained by using an arccosine value: cos⁻¹ Gy of an acceleration Gyapplied in the vertical direction or an arcsine value: sin⁻¹ Gz of anacceleration Gz applied in the lateral direction.

As described above, when an acceleration Gy applied in the verticaldirection and an acceleration Gz applied in the lateral direction can bedetected, a roll angle θr of a ship can be obtained by using anarccosine value: cos⁻¹ Gy of an acceleration Gy applied in the verticaldirection and an arcsine value: sin⁻¹ Gz of an acceleration Gz appliedin the lateral direction, but in order to accurately determine apresence/absence of a capsize accident of the ship, the change rate of aprocessed value to the change of a roll angle of a hull is desirablylarge when a roll angle θr of the hull is close to an angle for a nearcapsize (around 90 degrees). Thus, in the above described case, a rollangle θr is desirably obtained by using an arccosine value: cos⁻¹ Gy ofan acceleration Gy applied in the vertical direction.

In the above described embodiment, a two-axis acceleration sensor or athree-axis acceleration sensor is used as the acceleration detector 318,but the acceleration detector 318 may be comprised so as to detect onlyan acceleration Gx applied in a longitudinal direction when only acollision accident is detected and fuel supply to an engine is stopped.

Also, when only a capsize of a ship is detected and fuel supply to anengine is stopped in a capsize accident, at least one of an accelerationGy applied in a vertical direction and an acceleration Gz applied in alateral direction may be detected to arithmetically operate a roll angleθr with θr=cos⁻¹ Gy or θr=sin⁻¹ Gz, so that the processed value may becompared with a capsize threshold.

In a case where both of a collision accident and a capsize accident aredetected, instead of a two-axis acceleration sensor, a combination oftwo one-axis acceleration sensors may be used, and instead of athree-axis acceleration sensor, a combination of a two-axis accelerationsensor and one one-axis acceleration sensor may be used.

The acceleration detector 318 is preferably mounted in the controller ofthe power trim system 311 as in the above embodiment, but the presentinvention is not limited to the structure, and the acceleration detectormay be mounted to the hull 2 (for example, in the remote control unit4).

A roll angle of a ship can be obtained by a trigonometric function, butin arithmetically operating a roll angle, in order to increase the speedof the processing, a map for arithmetically operating a roll angle whichprovides a relationship between an acceleration and a roll angle ispreferably prepared, so that a roll angle can be arithmetically operatedby retrieving the map for an acquired acceleration and by performinginterpolation.

In each embodiment described above, a ship having an outboard enginesystem as a propulsion apparatus is used, but the present invention canalso be applied to any ship having a propulsion apparatus other than anoutboard engine system.

Now, various embodiment of an emergency engine shutoff apparatus forship according to the present invention will be organized and listedbelow:

(1) The acceleration detector 318 is provided so as to detect at leastan acceleration Gx applied in a longitudinal direction of a ship 1. Anaccident determining apparatus includes accident determining means fordetermining that a hull collides with something when an acceleration Gxapplied in the longitudinal direction of the ship exceeds a threshold inan acceleration or deceleration of the ship. Engine shutting off meansin accident 25 is provided for stopping fuel supply to an engine whenthe accident determining apparatus determines that an accident occurred.(2) The acceleration detector 318 is provided so as to detect at leastan acceleration Gy applied in a vertical direction of a ship 1. Anaccident determining apparatus includes accident determining means fordetermining that the ship capsized when a roll angle θr of the shipexceeds a preset threshold, the roll angle θr being obtained based on anarccosine value: cos⁻¹ Gy of the acceleration Gy applied in a verticaldirection of the ship. Engine shutting off means in accident 25 isprovided for stopping fuel supply to an engine when the accidentdetermining apparatus determines that a capsize accident occurred.(3) The acceleration detector 318 is provided so as to detect at leastan acceleration Gz applied in a lateral direction of a ship 1. Anaccident determining apparatus includes accident determining means fordetermining that the ship capsized when a roll angle θr of the shipexceeds a preset threshold, the roll angle θr being obtained based on anarcsine value: sin⁻¹ Gz of the acceleration Gz applied in a lateraldirection of the ship. Engine shutting off means in accident 25 isprovided for stopping fuel supply to an engine when the accidentdetermining apparatus determines that a capsize accident occurred.(4) The acceleration detector 318 is provided so as to detect anacceleration Gx applied in a longitudinal direction and an accelerationGy applied in a vertical direction of a ship 1. An accident determiningapparatus includes accident determining means for determining that ahull collided with something when an acceleration Gx applied in thelongitudinal direction of the ship exceeds a threshold in anacceleration or deceleration of the ship, and for determining that theship capsized when a roll angle θr of the ship exceeds a presetthreshold, the roll angle θr being obtained based on an arccosine value:cos⁻¹ Gy of the acceleration Gy applied in a vertical direction of theship. Engine shutting off means in accident 25 is provided for stoppingfuel supply to an engine when the accident determining apparatusdetermines that an accident occurred.(5) The acceleration detector 318 is provided so as to detect anacceleration Gx applied in a longitudinal direction and an accelerationGz applied in a lateral direction of a ship 1. An accident determiningapparatus includes accident determining means for determining that ahull collided with something when an acceleration Gx applied in thelongitudinal direction of the ship exceeds a threshold in anacceleration or deceleration of the ship, and for determining that theship capsized when a roll angle θr of the ship exceeds a presetthreshold, the roll angle θr being obtained based on an arcsine value:sin⁻¹ Gz of the acceleration Gz applied in a lateral direction of theship. Engine shutting off means in accident 25 is provided for stoppingfuel supply to an engine when the accident determining apparatusdetermines that an accident occurred.(6) The acceleration detector 318 is provided so as to detect anacceleration Gz applied in a lateral direction and an acceleration Gyapplied in a vertical direction of a ship 1. An accident determiningapparatus includes accident determining means for determining that theship capsized when a roll angle of the ship exceeds a preset threshold,the roll angle being obtained based on an arctangent value tan⁻¹(Gz/Gy)of a ratio (Gz/Gy) between an acceleration Gz applied in the lateraldirection and an acceleration Gy applied in the vertical direction ofthe ship. Engine shutting off means in accident 25 is provided forstopping fuel supply to an engine when the accident determiningapparatus determines that an accident occurred.(7) The acceleration detector 318 is provided so as to detect anacceleration Gx applied in a longitudinal direction, an acceleration Gyapplied in a vertical direction, and an acceleration Gz applied in alateral direction of a ship 1. An accident determining apparatusincludes accident determining means for determining that a hull collidedwith something when an acceleration Gx applied in the longitudinaldirection of the ship exceeds a threshold in an acceleration ordeceleration of the ship, and for determining that the ship capsizedwhen a roll angle θr of the ship exceeds a preset threshold, the rollangle being obtained based on an arctangent value tan⁻¹(Gz/Gy) of aratio (Gz/Gy) between an acceleration Gz applied in the lateraldirection and an acceleration Gy applied in the vertical direction ofthe ship. Engine shutting off means in accident 25 is provided forstopping fuel supply to an engine when the accident determiningapparatus determines that an accident occurred.(8) In each of the above structures (1) to (7), a propulsion apparatusof the ship is an outboard engine system, and the outboard engine systemis provided with a controller therein for controlling a trim angle ofthe outboard engine system, controlling an engine, and performing aprocess to construct the accident determining apparatus. In this case,the acceleration detector 318 is provided in the controller.(9) In a case where an engine is comprised so that fuel is providedthereto by a fuel injection apparatus 320 which has an injector and afuel pump for supplying fuel to the injector, the engine shutting offmeans in accident 25 may be comprised so as to shut off the engine bystopping driving at least one of the fuel pump and the injector to stopthe fuel supply to the engine when the accident determining apparatusdetermines that an accident occurred, or may be comprised of fuel supplystopping means for stopping fuel supply to the engine by stoppingdriving at least one of the fuel pump and the injector when the accidentdetermining apparatus determines that an accident occurred, and ignitionoperation stopping means for stopping any ignition operation of theengine when the accident determining apparatus determines that anaccident occurred.(10) Alternatively, the engine shutting off means in accident 25 may becomprised of ignition operation stopping means for stopping any ignitionoperation of the engine when the accident determining apparatusdetermines that an accident occurred.

Although the preferred embodiments of the invention have been describedand illustrated with reference to the accompanying drawings, it will beunderstood by those skilled in the art that there are by way ofexamples, and that various changes and modifications may be made withoutdeparting from the spirit and scope of the invention, which is definedonly to the appended claims.

1. An emergency engine shutoff apparatus for ship which shuts off anengine in an accident of a ship having a hull and a propulsion apparatushaving the engine as a driving source, comprising: an accelerationdetector for detecting an acceleration applied onto the hull; anaccident determining apparatus which includes accident determining meansfor determining a presence/absence of an accident based on an output ofthe acceleration detector, on the premise that a collision withsomething and/or a capsize of the hull is an accident to be determined;and engine shutting off means in accident for shutting off the enginewhen the accident determining apparatus determines that an accidentoccurred.
 2. The emergency engine shutoff apparatus for ship accordingto claim 1, wherein the acceleration detector is provided so as todetect at least an acceleration Gx applied in a longitudinal directionof the ship, and the accident determining apparatus includes accidentdetermining means for determining that the hull collided with somethingwhen an acceleration Gx applied in the longitudinal direction of theship exceeds a threshold in an acceleration or deceleration of the ship.3. The emergency engine shutoff apparatus for ship according to claim 1,wherein the acceleration detector is provided so as to detect at leastan acceleration Gy applied in a vertical direction of the ship, and theaccident determining apparatus includes accident determining means fordetermining that the ship capsized when a roll angle θr of the shipexceeds a preset threshold, the roll angle θr being obtained based on anarccosine value: cos⁻¹ Gy of the acceleration Gy applied in a verticaldirection of the ship.
 4. The emergency engine shutoff apparatus forship according to claim 1, wherein the acceleration detector is providedso as to detect at least an acceleration Gz applied in a lateraldirection of the ship, and the accident determining apparatus includesaccident determining means for determining that the ship capsized when aroll angle θr of the ship exceeds a preset threshold, the roll angle θrbeing obtained based on an arcsine value: sin⁻¹ Gz of the accelerationGz applied in a lateral direction of the ship.
 5. The emergency engineshutoff apparatus for ship according to claim 1, wherein theacceleration detector is provided so as to detect an acceleration Gxapplied in a longitudinal direction and an acceleration Gy applied in avertical direction of the ship, and the accident determining apparatusincludes accident determining means for determining that the hullcollided with something when the acceleration Gx applied in thelongitudinal direction of the ship exceeds a threshold in anacceleration or deceleration of the ship, and for determining that theship capsized when a roll angle θr of the ship exceeds a presetthreshold, the roll angle θr being obtained based on an arccosine value:cos⁻¹ Gy of the acceleration Gy applied in a vertical direction of theship.
 6. The emergency engine shutoff apparatus for ship according toclaim 1, wherein the acceleration detector is provided so as to detectan acceleration Gx applied in a longitudinal direction and anacceleration Gz applied in a lateral direction of the ship, and theaccident determining apparatus includes accident determining means fordetermining that the hull collided with something when the accelerationGx applied in the longitudinal direction of the ship exceeds a thresholdin an acceleration or deceleration of the ship, and for determining thatthe ship capsized when a roll angle θr of the ship exceeds a presetthreshold, the roll angle θr being obtained based on an arcsine value:sin⁻¹ Gz of the acceleration Gz applied in a lateral direction of theship.
 7. The emergency engine shutoff apparatus for ship according toclaim 1, wherein the acceleration detector is provided so as to detectan acceleration Gz applied in a lateral direction and an acceleration Gyapplied in a vertical direction of the ship, and the accidentdetermining apparatus includes accident determining means fordetermining that the ship capsized when a roll angle of the ship exceedsa preset threshold, the roll angle being obtained based on an arctangentvalue tan⁻¹(Gz/Gy) of a ratio (Gz/Gy) between the acceleration Gzapplied in the lateral direction and the acceleration Gy applied in thevertical direction of the ship.
 8. The emergency engine shutoffapparatus for ship according to claim 1, wherein the accelerationdetector is provided so as to detect an acceleration Gx applied in alongitudinal direction, an acceleration Gy applied in a verticaldirection, and an acceleration Gz applied in a lateral direction of theship, and the accident determining apparatus includes accidentdetermining means for determining that the hull collided with somethingwhen the acceleration Gx applied in the longitudinal direction of theship exceeds a threshold in an acceleration or deceleration of the ship,and for determining that the ship capsized when a roll angle θr of theship exceeds a preset threshold, the roll angle being obtained based onan arctangent value tan⁻¹(Gz/Gy) of a ratio (Gz/Gy) between theacceleration Gz applied in the lateral direction and the acceleration Gyapplied in the vertical direction of the ship.
 9. The emergency engineshutoff apparatus for ship according to claim 1, wherein the propulsionapparatus is an outboard engine system, and the outboard engine systemis provided with a controller therein for controlling a trim angle ofthe outboard engine system, controlling the engine, and performing aprocess to construct the accident determining apparatus, and theacceleration detector is provided in the controller.
 10. The emergencyengine shutoff apparatus for ship according to claim 1, wherein theengine is comprised so that fuel is supplied thereto by an fuelinjection apparatus which has an injector and a fuel pump for supplyingfuel to the injector, and the engine shutting off means in accident iscomprised so as to shut off the engine by stopping driving at least oneof the fuel pump and the injector to stop fuel supply to the engine whenthe accident determining apparatus determines that an accident occurred.11. The emergency engine shutoff apparatus for ship according to claim1, wherein the engine is comprised so that fuel is supplied thereto byan fuel injection apparatus which has an injector and a fuel pump forsupplying fuel to the injector, and the engine shutting off means inaccident is comprised of fuel supply stopping means for stopping fuelsupply to the engine by stopping driving at least one of the fuel pumpand the injector when the accident determining apparatus determines thatan accident occurred, and ignition operation stopping means for stoppingany ignition operation of the engine when the accident determiningapparatus determines that an accident occurred.
 12. The emergency engineshutoff apparatus for ship according to claim 1, wherein the engineshutting off means in accident is comprised of ignition operationstopping means for stopping an ignition operation of the engine when theaccident determining apparatus determines that an accident occurred.